During the past 5 years of her K24 award, the candidate has provided mentoring to 55 clinical research trainees, including 30 physician/nurse research trainees. For this K24 renewal application, Dr. John- Stewart proposes to mentor a new cadre of clinician-researchers focused on pediatric HIV-1 infected and exposed children. She has already identified 15 trainees, including pediatricians, internists, epidemiologists, and nurses for long-term mentorship in the K24 renewal. Using one-on-one in person meetings, group mentoring (formal weekly analyses meetings), distance-mentoring (for trainees in Nairobi) and peer and co- mentoring, Dr. John-Stewart anticipates investing 20% FTE in mentoring a cadre of clinical researchers committed to translational global pediatric HIV-1-related research. Research: During the 5 years of her K24 award, Dr. John-Stewart has been extremely productive, increasing from 43 to >120 publications in peer-reviewed journals and leads several research grants focused on women and children. For the K24 renewal, research will utilize existing cohorts to focus on pediatric HIV-1 in 3 inter- related domains - immunology, growth, and cognition. She proposes to extend follow-up of a cohort of children who received treatment during infancy >3 years, including previous randomization to interrupted vs. continued therapy. Extending this cohort will enable long-term comparisons of immune recovery and identification of immune correlates of more prolonged immune sustenance during interruption to inform potential future therapeutic vaccine strategies. This and other ongoing or historical cohorts will be used for analyses of growth, micronutrient levels, and nutritional supplementation in HIV-1 exposed and infected treated children. In ongoing cohorts, cognitive assessments will be incorporated for all participating children at annual intervals to identify prevalence and cofactor of cognitive delay and develop future studies. Research strategies used by mentored trainees will range from molecular epidemiology to implementation science and provide inter-disciplinary translational impact.